Sudbury Road Landfill

The Sudbury Road Landfill is about 4 miles west of the City of Walla Walla and ½ mile north of Highway 12. The landfill sits on 125 acres in a mainly rural area. The City of Walla Walla owns and operates the landfill, which is used for disposal of the area's municipal solid waste (MSW). It disposed MSW in unlined areas from 1978 to 2006. It continues to dispose of MSW today, though in an area of the landfill that is lined.
 
Since 1977, the City has tested groundwater from wells around the landfill. In 2001, the City installed a new well. Tests on water from this new well show the groundwater contains chemicals, including volatile organic compounds, at levels that may be harmful to human health and the environment. Follow-up tests show the landfill is at least in part contributing to these impacts to groundwater.
 
In January 2011, the City did some work at the site to prevent groundwater impacts from becoming worse. The City placed a cover and installed gas and stormwater control systems over one unlined landfill cell, and diverted stormwater run-on away from another unlined landfill cell.

In May 2011, the Washington Department of Ecology and the City of Walla Walla worked through an Agreed Order requiring further investigation of contaminants from the site. The Agreed Order required the City of Walla Walla to conduct a Remedial Investigation and Feasibility Study, which it completed in 2012-2014. The City found chemicals (tetrachloroethylene and vinyl chloride) within the site at levels that need cleanup. It did not find these chemicals off-site at levels that need cleanup. In the study, preferred cleanup actions include improvements to landfill cover and stormwater controls, installation of gas control system, long-term groundwater and gas monitoring, and restrictions on property use. 

Through a May 2015 Consent Decree, the City began remedy construction as directed by a Cleanup Action Plan (CAP). The CAP included installation of landfill gas controls in three distinct areas, improved cover over two areas, improved grading to shed stormwater in one area, installation of stormwater controls at the northern edge of the landfill, ongoing groundwater monitoring, and property use restrictions through an Environmental Covenant. The City completed all construction in 2017, filed the Environmental Covenant in 2019, and monitors groundwater quarterly.

Periodic review

Ecology completed its first Periodic (5-Year) Review of cleanup effectiveness in 2022. Both contaminants of concern in groundwater (tetrachloroethylene and vinyl chloride) have decreased and have been at or below cleanup levels since March 2019 and December 2019, respectively.